Calalysts, especially for producing polyisocyanate polyaddition products

ABSTRACT

Catalysts contain, as structural units, at least one tertiary amino group and at least one group which, after its decomposition, is capable of complexing or protonating the tertiary amino group.

[0001] The present invention relates to catalysts containing, asstructural units, at least one tertiary amino group and at least onegroup which, after its decomposition, preferably its hydrolysis, iscapable of complexing or protonating the tertiary amine, and the use ofsuch catalysts. The present invention furthermore relates to processesfor the preparation of polyisocyanate polyadducts, for example flexibleintegral, semirigid, rigid and flexible foams and microcellular foams,preferably flexible polyurethane foams, in particular for mattresses,upholstery or carpets for automotive or furniture applications, shoesoles and steering wheels, and products obtainable in this manner.

[0002] The preparation of polyisocyanate polyadducts by reactingpolyisocyanates with compounds reactive toward isocyanates in thepresence of catalysts which accelerate the reaction of the substancesreactive toward isocyanates with isocyanates and, if required, blowingagents, additives and/or assistants is generally known.

[0003] As in the case of other plastics, polyisocyanate polyadducts aresubject to aging processes which generally lead to a deterioration inthe performance characteristics with increasing time. Major aginginfluences are, for example, hydrolysis, photooxidation and thermaloxidation, which lead to breaking of bonds in the polymer chains. In thecase of polyisocyanate polyadducts, for example polyurethanes, alsoreferred to below as PUR, in particular the action of moisture and to aneven greater extent the combination of moisture and elevatedtemperatures results in hydrolytic cleavage of the urethane and ureabonds.

[0004] Not only is this cleavage evident from a significantdeterioration in the performance characteristics but it also leads tothe formation of primary aromatic amines, e.g. toluenediamine (TDA) anddiaminodiphenylmethane (MDA), or primary aliphatic amines, for examplehexamethylenediamine or isophoronediamine.

[0005] As has been found in tests, the amine formation is influenced bya number of parameters. In particular, high temperatures from 80° C. incombination with high atmospheric humidity lead to hydrolytic cleavageof the urethane and urea bonds. Such conditions are important for thematerial polyurethane in various applications.

[0006] A further parameter which significantly influences the formationof primary amines is the type and amount of the catalysts used. As wasshown in various experiments, the catalysts contained in polyurethanesystems and necessary for the urethanization and blowing reaction alsocatalyzed the hydrolytic cleavage reaction to a considerable extent. Thepresence of catalysts is thus a very decisive precondition for thehydrolysis of the urethane and urea bonds. Moreover, it was possible toshow that the efficiency of the hydrolysis depends to a high degree onthe activity and on the type of the catalyst and on whether the catalystremains in the system or can migrate out of the material. In particular,tertiary amine catalysts having reactive functional groups, such as OHand NH₂, accelerate the amine formation by considerably lowering theactivation energy for the cleavage reaction. The functional groupsresult in the incorporation of the catalysts into the PUR net workforming, and the products thus prepared have the advantage of less odorand fogging problems since the catalysts cannot escape by diffusionafter the preparation of the final PUR product. The same applies toformulations containing polyols which were prepared using primary orsecondary amines as initiator molecules and thus have catalyticallyactive centers. Such polyols have increasingly been used recently. Inthe case of polyurethane parts which comprise such constituents and, incertain applications, are exposed to particular moist and warmconditions, the formation of primary aromatic amines as cleavageproducts cannot be ruled out. In the case of foams with amine catalystswhich do not contain any functional groups capable of beingincorporated, these catalysts on the other hand generally escape only ashort time after the preparation of the final product or during theaging of the foams. In the case of such foams, moist and warm conditionslead to substantially lower aromatic amine contents.

[0007] The problems described at the outset consequently occur to agreater extent when using catalysts capable of being incorporated. Thesecatalysts have at least one group reactive toward isocyanates and, owingto the reaction with the isocyanates, are covalently bonded in the PUR.As a result, the fogging behavior is improved since the catalyst doesnot evaporate from the PUR but its remaining in PUR leads to increasedcleavage of the urethane groups.

[0008] It is an object of the present invention to providepolyisocyanate polyadducts which, after their preparation, have lesstendency to cleavage of their urethane and urea bonds.

[0009] We have found that this object is achieved by the catalystsdescribed at the outset.

[0010] The present invention therefore relates to catalysts, inparticular those which catalyze the reaction of isocyanates withcompounds reactive toward isocyanates, in particular hydroxyl groups,containing, as structural units, at least one tertiary amino group,preferably from 1 to 20, particularly preferably from 1 to 5 tertiaryamino groups, and at least one group, preferably from 1 to 60,particularly preferably from 1 to 10 groups, which, after theirdecomposition, preferably their hydrolysis, are capable of complexing orprotonating tertiary amino groups.

[0011] Owing to the tertiary amine in their starting structure, thesenovel catalysts catalyze the reaction of isocyanates with compoundsreactive toward isocyanates, usually compounds including water, whichhave at least one hydroxyl, thiol and/or primary and/or secondary aminogroup, to give urethanes and/or ureas. This catalytic action of thestarting structure is surprisingly not adversely affected by at leastone additional hydrolyzable group.

[0012] After the catalysts have been able to display their catalyticactivity in the process for the preparation of the polyisocyanatepolyadducts the novel catalysts are increasingly decomposed, inparticular hydrolyzed, during the subsequent storage of thepolyisocyanate polyadducts or their use, in particular under moistand/or warm conditions, which also promote the cleavage of the urethanestructures. The decomposition of the catalysts leads to the formation ofat least one group which is capable of complexing or protonating thetertiary amino group of the catalyst. As a result of this complexingand/or protonation of the tertiary amino group, the catalytically activecenter is blocked and the catalyst thus deactivated. Since, as describedat the outset, this catalytically active center also catalyzes thecleavage of the urethane structures the object, i.e. of avoidingcleavage, is achieved by the novel catalysts. The novel catalystsfurthermore have the advantage that addition of compounds whichdeactivate the catalysts is superfluous during or after the preparationof the polyisocyanate polyadducts since the catalyst deactivates itself,for example during hydrolytic aging.

[0013] The catalysts are thus preferably used in polyisocyanatepolyadducts both for catalysis in the preparation and for stabilizationof the polyisocyanate polyadducts, in particular polyurethanes, tocleavage of the urethane and urea bonds, for example by blocking ofamine catalysts by protonation of the catalytically active centers.Moreover, some forms of these catalysts in polyisocyanate polyadductscan be used for the reaction with amino groups, for example to giveamides, in the polyisocyanate polyadducts. In addition, the catalystscan be converted during the aging into an ionic form (salt) which doesnot contribute to the fogging behavior of the system. The diffusion ofamines from polyisocyanate polyadducts and the cleavage of the urethanebond, for example by amine catalysts present in the polyisocyanatepolyadducts, can be reduced according to the invention.

[0014] Surprisingly, it was found that the hydrolyzable groups as amixture with isocyanates or in compounds reactive toward isocyanates,for example polyether polyalcohols or polyester polyalkohols, are stableat room temperature, i.e. 25° C. It was also found that the novelcatalysts, which are used in the preparation of polyisocyanatepolyadducts, withstand the preparation process virtually without damageand are deactivated only to a minor extent during the processingprocedure itself.

[0015] In general, groups which can be hydrolyzed and, after thehydrolysis, have at least one group which is capable of complexing orprotonating tertiary amino groups may be present as the group which,after its decomposition, is capable of complexing or protonating thetertiary amino group or generally the tertiary amine. For example,esters and/or acid anhydrides, preferably carboxylic esters, sulfonicesters, carboxylic anhydrides, lactones, sultones, phosphoric estersand/or phosphonic esters, are suitable as such hydrolyzable groups. Theacid groups present in free form after decomposition of the catalyst arecapable of protonating or complexing and hence inhibiting the tertiaryamine of the catalyst. Polymer-analogous catalysts, for example preparedfrom polyimine (reacted in a reaction analogous to a Michael additionwith abovementioned substances, such as carboxylic esters), or catalystswhose free amino groups are reacted with corresponding polymer-analogousvinylcarboxylic esters and/or vinylcarboxylic anhydrides are alsosuitable.

[0016] In addition to the groups described above, the catalysts mayfurthermore also have at least one group reactive toward isocyanates,for example a hydroxyl, thiol and/or primary and/or secondary aminogroup, preferably a hydroxyl and/or primary and/or secondary aminogroup, particularly preferably a hydroxyl group.

[0017] The synthesis of catalytically active tertiary amines isgenerally known and preparation methods are described, for example, inHouben Weyl, volumes 11/1 and 11/2. For example, primary and secondaryamines can be converted into tertiary amines by addition at doublebonds. Thus, catalysts capable of being incorporated can be preparedfrom sodium allylate and secondary amines; for example, piperidine andsodium allylate react to give N-(3-hydroxypropyl)piperidine, which canbe further esterified with a carboxylic acid or a carboxylic anhydrideor a carbonyl chloride.

[0018] The preparation of the novel catalysts can also be carried out,for example, according to the generally known Michael addition byreacting primary and/or secondary amines with α,β-unsaturated carbonylcompounds, for example anhydrides or esters or polyesters of methacrylicacid, itaconic acid, acrylic acid and/or maleic acid. Examples ofsuitable starting substances are methyl acrylate, ethyl acrylate, propylacrylate, tert-butyl acrylate, phenyl acrylate, methyl methacrylate,dimethyl itaconate, trimethyl aconitate, triethyl aconitate, tributylaconitate, ethyl methacrylate, propyl methacrylate, tert-butylmethacrylate, phenyl methacrylate, maleic anhydride, dimethyl maleate,diallyl maleate, dibutyl maleate, diethyl maleate, diethyl fumarate,dimethyl fumarate and/or dibutyl fumarate as carbonyl compounds andprimary and secondary aliphatic or cycloaliphatic amines of 1 to 100carbon atoms and 1 to 50 nitrogen atoms, e.g. morpholine,N-bis(3-di-methylaminopropyl)amine, piperidine, N-methylpiperazine,N-ethylpiperazine, N-propylpiperazine, pyrrolidine,N-aminoethylpiperazine, aminopropylimidazole,N-(2-aminoethyl)morpholine, 1,6-di(2-aminoethyl)piperazine,hexahydrotriazine, preferably those amines which also have 1-5 OHfunctions in addition to the amino function, e.g.1-(2-hydroxyethyl)piperazine and1,3,5-tri(2-hydroxyethyl)-hexahydrotriazine as primary and secondaryamines.

[0019] The reaction can be carried out by generally known methods, whichare known for the Michael addition.

[0020] Novel catalysts can also be prepared by reacting amines withother compounds having activated double bonds. Thus, amines can becoupled to unsaturated nitrites. After hydrolysis of the nitrile group,it can be converted into an ester group. Catalysts are also obtained byan addition reaction of a secondary amine with a vinylphosphonic ester,for example by reacting N-methylpiperazine and diethyl vinylphosphonate.

[0021] Those compounds which contain at least just as many or moregroups which are decomposable and, after decomposition, have acomplexing or protonating action as they have catalytically activecenters are preferred.

[0022] A further synthesis route to novel catalysts is to react primaryand secondary amines with alkylene oxides, e.g. ethylene oxide orpropylene oxide. The hydroxyalkylamines thus formed can be esterified bya known method with carboxylic esters, carbonyl chlorides or carboxylicanhydrides.

[0023] The novel catalysts are preferably used in the generally knownprocesses for the preparation of polyisocyanate polyadducts, preferablypolyurethanes which may have isocyanurate and/or urea structures,particularly preferably flexible polyurethane foams.

[0024] The novel catalysts are used in the processes for the preparationof polyisocyanate polyadducts preferably in an amount of from 0.01 to15, particularly preferably from 0.05 to 10, in particular from 0.05 to5, % by weight, based on the weight of the polyisocyanate polyadduct.The novel catalysts have a molecular weight of from 100 to 5000,preferably from 100 to 3000 and particularly preferably from 100 to 2000g/mol.

[0025] The preparation of polyisocyanate polyadducts usually by reactingpolyisocyanates with compounds reactive toward isocyanates, in thepresence of catalysts which accelerate the reaction of the substancesreactive toward isocyanates with isocyanates and, if required, blowingagents, additives and/or assistants, is generally known. For example,compact or cellular, for example microcellular, flexible, semirigid orrigid polyurethane foams, thermoplastic polyurethanes or polyurethaneelastomers can be prepared as polyisocyanate polyadducts by conventionalprocesses using the novel catalysts. Preferably, the catalysts presentedare used in processes for the preparation of polyurethane elastomers orfoamed polyisocyanate polyadducts, preferably flexible polyurethanefoams, in particular having a density of from 15 to 300, preferably from15 to 120, kg/m³, preferably mattresses and/or upholstery for furnitureor carpets, particularly preferably hospital mattresses or flexible PURfoam articles which are exposed to moist and warm conditions, byreacting isocyanates with compounds reactive toward isocyanates, in thepresence of catalysts, blowing agents and, if required, additives and/orassistants. These products, i.e. in particular the upholstery forfurniture and/or carpets or the mattresses, are increasingly beingtreated with hot steam for cleaning or disinfection, with the resultthat the advantages according to the invention are especially pronouncedespecially in the case of these products.

[0026] The generally customary starting materials for the preparation ofthe polyisocyanate polyadducts are described by way of example below.

[0027] The isocyanates used may be the conventional aliphatic,cycloaliphatic, araliphatic and preferably aromatic organic isocyanates,preferably polyfunctional isocyanates, particularly preferablydiisocyanates.

[0028] Specific examples are alkylene diisocyanates having 4 to 12carbon atoms in the alkylene radical, such as dodecane1,12-diiso-cyanate, 2-ethyltetramethylene 1,4-diisocyanate,2-methyl-pentamethylene 1,5-diisocyanate, tetramethylene1,4-diisocyanate and preferably hexamethylene 1,6-diisocyanate;cycloaliphatic diisocyanates, such as cyclohexane 1,3- and1,4-diisocyanate and any desired mixtures of these isomers,1-isocyanato-3,3,5-trimethyl-5-isocyanatomethylcyclohexane (isophoronediisocyanate), hexahydrotoluene 2,4- and 2,6-diisocyanate and thecorresponding isomeren mixtures, dicyclohexylmethane 4,4′-, 2,2′- and2,4′-diisocyanate and the corresponding isomer mixtures, aromatic di-and polyisocyanates, e.g. toluene 2,4- and 2,6-diisocyanate (TDI) andthe corresponding isomer mixtures, diphenylmethane 4,4′-, 2,4′- and2,2′-diisocyanate (MDI) and the corresponding isomer mixtures,naphthaline 1,5-diisocyanate (NDI), mixtures of diphenylmethane 4,4′-and 2,4′-diisocyanates, mixtures of NDI and diphenylmethane 4,4′- and/or2,4′-diisocyanates, 3,3′-dimethyl-4,4′-diisocyanatobiphenyl (TOBI),mixtures of TOBI and diphenylmethane 4,4′- and/or 2,4′-diisocyanates,polyphenylpolymethylene polyisocyanates, mixtures of diphenylmethane4,4′-, 2,4′- and 2,2′-diisocyanates and polyphenylpolymethylenepolyisocyanates (crude MDI) and mixtures of crude MDI and toluenediisocyanates. The organic di- and polyisocyanates can be usedindividually or in the form of their mixtures.

[0029] Frequently, modified polyfunctional isocyanates, i.e. productswhich are obtained by chemical reaction of organic di- and/orpolyisocyanates, are also often used. Examples are di- and/orpolyisocyanates containing ester, urea, biuret, allophanate,carbodiimide, isocyanurate, uretdione and/or urethane groups. Suitablespecific examples are: organic, preferably aromatic polyisocyanatescontaining urethane groups and having NCO contents of from 33.6 to 3.5,preferably from 31 to 12, % by weight, based on the total weight,modified diphenylmethane 4,4′-diisocyanate, modified diphenylmethane4,4′- and 2,4′-diisocyanate mixtures, modified NDI, modified TOBI,modified crude MDI and/or toluene 2,4- or 2,6-diisocyanate, examples ofdi- or polyoxyalkylene glycols which may be used individually or asmixtures being diethylene and dipropylene glycol, polyoxyethylene,polyoxypropylene and polyoxypropylene polyoxyethylene glycols, -triolsand/or tetrols. NCO-containing prepolymers having NCO contents of from25 to 3.5, preferably from 21 to 14, % by weight, based on the totalweight, prepared from, for example, polyester polyols and/or preferablypolyether polyols and diphenylmethane 4,4′-diisocyanate, mixtures ofdiphenylmethane 2,4′- and 4,4′-diisocyanate, NDI, TOBI, mixtures of NDIand isomers of MDI, toluene 2,4- and/or 2,6-diisocyanates or crude MDI,are also suitable. Furthermore, liquid polyisocyanates containingcarbodiimide groups and/or isocyanurate rings and having NCO contents offrom 33.6 to 15, preferably from 31 to 21, % by weight, based on thetotal weight, for example based on diphenylmethane 4,4′-, 2,4′- and/or2,2′-diisocyanate, NDI, HDI, TOBI and/or toluene 2,4- and/or2,6-diisocyanate, have proven useful.

[0030] The modified polyisocyanates can, if required, be mixed with oneanother or with unmodified organic polyisocyanates, e.g. diphenylmethane2,4′- or 4,4′-diisocyanate, NDI, TOBI, crude MDI or toluene 2,4- and/or2,6-diisocyanate.

[0031] Preferably used isocyanates in the novel mixtures or processesare diphenylmethane 4,4′-, 2,4′- and/or 2,2′-diisocyanate, toluene 2,4-and/or 2,6-diisocyanate, NDI, hexamethylene diisocyanate and/orisophorone diisocyanate, it being possible to use these isocyanates bothin any desired mixtures and, as described above, in modified form.

[0032] Compounds which are reactive toward isocyanates and usually haveat least two reactive hydrogen atoms, usually hydroxyl and/or aminogroups, and which can expediently be used are those having afunctionality of from 2 to 8, preferably from 2 to 6, and a molecularweight of, usually, from 60 to 10 000. For example, polyether polyaminesand/or preferably polyols selected from the group consisting of thepolyether polyols, polyester polyols, polythioether polyols,polyesteramides, hydroxyl-containing polyacetals and hydroxyl-containingaliphatic polycarbonates or mixtures of at least two of said polyolshave proven useful. Polyester polyols and/or polyether polyols which canbe prepared by known processes are preferably used.

[0033] The polyester polyols preferably have a functionality of from 2to 4, in particular from 2 to 3, and a molecular weight of, usually,from 500 to 3 000, preferably from 1 200 to 3 000, in particular from 1800 to 2 500.

[0034] The polyether polyols have a functionality of, preferably, from 2to 6 and usually molecular weights of from 500 to 8 000.

[0035] Other examples of suitable polyether polyols are polymer-modifiedpolyether polyols, preferably graft polyether polyols, in particularthose based on styrene and/or acrylonitrile, which can be prepared by insitu polymerization of acrylonitrile, styrene or preferably mixtures ofstyrene and acrylonitrile.

[0036] The polyether polyols as well as the polyester polyols can beused individually or in the form of mixtures. Furthermore, they can bemixed with the graft polyether polyols or polyester polyols andhydroxyl-containing polyester amides, polyacetals and/or polycarbonates.

[0037] The polyol components used are high-functionality polyols, inparticular polyether polyols based on high-functionality alcohols, sugaralcohols and/or saccharides, as initiator molecules for rigidpolyurethane foams which may have isocyanurate structures, anddifunctional and/or trifunctional polyether polyols and/or polyesterpolyols based on glycerol and/or trimethylolpropane and/or glycols asinitiator molecule or alcohols to be esterified for flexible foams. Thepolyether polyols are prepared by a known technology. Suitable alkyleneoxides for the preparation of the polyols are, for example,tetrahydrofuran, 1,3-propylene oxide, 1,2- and 2,3-butylene oxide,styrene oxide and preferably ethylene oxide and 1,2-propylene oxide. Thealkylene oxides can be used individually, alternately in succession oras mixtures. Preferably used alkylene oxides are those which lead toprimary hydroxyl groups in the polyol. Particularly preferably usedpolyols are those which have been alkoxylated with ethylene oxide at theend of the alkoxylation and thus have primary hydroxyl groups. For thepreparation of thermoplastic polyurethanes, polyols having afunctionality of from 2 to 2.2 and no crosslinking agents are preferablyused.

[0038] Furthermore, chain extenders and/or crosslinking agents can beused as compounds reactive toward isocyanates. For example, formodifying the mechanical properties, e.g. the hardness, of thepolyisocyanate polyadducts prepared using these substances, the additionof chain extenders, crosslinking agents or, if required, also mixturesthereof may prove advantageous. The chain extenders and/or crosslinkingagents used may be water, diols and/or triols having molecular weightsof from 60 to <500, preferably from 60 to 300. For example, aliphatic,cycloaliphatic and/or araliphatic diols of 2 to 14, preferably 4 to 10,carbon atoms, e.g. ethylene glycol, 1,3-propanediol, 1,10-decanediol,o-, m- and p-dihydroxy-cyclohexane, diethylene glycol, dipropyleneglycol and preferably 1,4-butanediol, 1,6-hexanediol andbis(2-hydroxyethyl)-hydroquinone, triols, such as 1,2,4- and1,3,5-trihydroxycyclohexane, glycerol and trimethylolpropane, and lowmolecular weight hydroxyl-containing polyalkylene oxides based onethylene oxide and/or 1,2-propylene oxide and diols and/or triols aresuitable as initiator molecules.

[0039] If chain extenders, crosslinking agents or mixtures thereof areused for the preparation of the polyisocyanate polyadducts, they areexpediently employed in an amount of from 0 to 20, preferably from 2 to8, % by weight, based on the weight of the compounds reactive toward theisocyanates, thermoplastic polyurethanes preferably being preparedwithout crosslinking agents.

[0040] In addition to the novel catalysts, generally customary compoundsmay be used as catalysts, for example organic amines, e.g.triethylamine, triethylenediamine, tributylamine, dimethylbenzylamine,N,N,N′,N′-tetramethylethylenediamine,N,N,N′,N′-tetramethylbutanediamine,N,N,N′,N′-tetramethylhexane-1,6-diamine, dimethylcyclohexylamine,pentamethyldipropylenetriamine, pentamethyldiethylenetriamine,3-methyl-6-dimethylamino-3-azapentol, dimethylaminopropylamine,1,3-bisdimethylaminobutane, bis(2-dimethylaminoethyl) ether,N-ethylmorpholine, N-methylmorpholine, N-cyclohexylmorpholine,2-dimethylamnoethoxyethanol, dimethylethanolamine,tetramethylhexamethylenediamine, dimethylamino-N-methyl-ethanolamine,N-methylimidazole, N-(3-aminopropyl)imidazole,N-(3-aminopropyl)-2-methylimidazole, 1-(2-hydroxyethyl)imidazole,N-formyl-N,N′-dimethylbutylenediamine, N-dimethylaminoethyl- morpholine,3,3′-bisdimethylaminodi-n-propylamine and/or2,2′-dipiperazinediisopropyl ether, dimethylpiperazine,N,N′-bis(3-aminopropyl)ethylenediamine and/ortris(N,N-dimethylaminopropyl)-s-hexahydrotriazine, or mixturescontaining at least two of said amines, higher molecular weight tertiaryamines, as described, for example, in DE-A 28 12 256, also beingpossible. Furthermore, conventional organic metal compounds may be usedas catalysts for this purpose, preferably organic tin compounds, such astin(II) salts of organic carboxylic acids, e.g. tin(II) acetate, tin(II)octanoate, tin(II) ethylhexanoate and tin(II) laurate, and thedialkyltin(IV) salts of organic carboxylic acids, e.g. dibutyltindiacetate, dibutyltin dilaurate, dibutyltin maleate and dioctyltindiacetate. Preferably, tertiary aliphatic and/or cycloaliphatic aminesmay be present in the mixtures, particularly preferablytriethylenediamine, bis(dimethylaminoethyl) ether or2-(2-dimethylaminoethoxy)ethanol.

[0041] Generally known blowing agents, e.g. substances which have aboiling point under atmospheric pressure of from 40° C. to 120° C.,gases and/or solid blowing agents and/or water can, if required, be usedin conventional amounts as blowing agents, preferably for thepreparation of foamed polyurethanes, for example carbon dioxide, alkanesand/or cycloalkanes, such as isobutane, propane, n-butane, isobutane,n-pentane and cyclopentane, ethers, for example diethyl ether, methylisobutyl ether and dimethyl ether, nitrogen, oxygen, helium, argon,nitrous oxide, halogenated hydrocarbons and/or partially halogenatedhydrocarbons, such as trifluoromethane, monochlorotrifluoroethane,difluoroethaane, pentafluoroethane, tetrafluoroethane or mixtures whichcontain at least two of the blowing agents stated by way of example.

[0042] Examples of assistants and/or additives are surfactants, foamstabilizers, cell regulators, fillers, dyes, pigments, flameproofingagents, hydrolysis stabilizers and fungistatic and bacteriostaticsubstances.

[0043] Usually, the organic polyisocyanates and the compounds reactivetoward isocyanates and having a molecular weight of from 60 to 10 000g/mol are reacted in amounts such that the ratio of the number ofequivalents of NCO groups of the polyisocyanates to the sum of thereactive hydrogen atoms of the compounds reactive toward isocyanates isfrom 0.5:1 to 5:1, preferably from 0.5:1 to 3:1, preferably from 0.5:1to 2:1 and in particular from 0.5:1 to 1.5:1.

[0044] It may be advantageous if the polyurethanes contain at least someof the isocyanurate groups in bound form. In these cases a ratio of NCOgroups of the polyisocyanates to the sum of the reactive hydrogen atomsof from 1.5:1 to 60:1, preferably from 1.5:1 to 8:1, can preferably bechosen.

[0045] The polyisocyanate polyadducts can be prepared, for example, bythe one-shot process or the known prepolymer process, for example withthe aid of the high pressure or low pressure technique in open or closedmolds, reaction extruders or belt units.

[0046] Preferably, foamed polyisocyanate polyadducts, for example foamedpolyurethanes and/or polyisocyanates are prepared with the novelmixtures.

[0047] It has proven advantageous to prepare the polyisocyanatepolyadducts by the two-component process and to combine the compoundsreactive toward isocyanates and, if required, the catalysts, blowingagents and/or assistants and/or additives in the A component and to usethe isocyanates and catalysts and/or blowing agents as the B component.

[0048] The examples which follow illustrate the invention.

EXAMPLES Example 1

[0049] Synthesis of an Incorporatable Catalyst From1-(2-hydroxyethyl)piperazine and tert-butyl Acrylate

[0050] In a 500 ml four-necked flask with reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 65.1 g of1-(2-hydroxyethyl)piperazine were dissolved in 75 ml of methanol. 64.09g of tert-butyl acrylate were added dropwise to the solution in thecourse of 60 minutes while stirring. Heating was carried out to 60° C.and stirring was effected for 2 hours at this temperature. The mixturewas then cooled to room temperature. The product was left to stand for24 hours. The methanol and the excess tert-butyl acrylate were thendistilled off under reduced pressure via a rotary evaporator.

Example 2

[0051] Synthesis of a Catalyst From 1-(2-hydroxyethyl)piperazine andMethyl Acrylate

[0052] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 80 g of1-(2-hydroxyethyl)piperazine were dissolved in 75 ml of methanol. 52.9 gof methyl acrylate were added dropwise to the solution while stirring.Heating was carried out to 60° C. and stirring was effected for 2 hoursat this temperature. The product was left to stand for 24 hours. Themethanol and the excess methyl acrylate were then distilled off underreduced pressure via a rotary evaporator.

Example 3

[0053] Synthesis of a Catalyst From 1-(2-hydroxyethyl)piperazine andDimethyl Maleate

[0054] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration), and internal thermometer, 65 g of1-(2-hydroxyethyl)piperazine were dissolved in 75 ml of methanol. 71.96g of dimethyl maleate were added dropwise to the solution whilestirring. After the addition of about 50% of the dimethyl maleate, awhitish precipitate settled out.

Example 4

[0055] Synthesis of a Catalyst from Methyl Acrylate and Piperidine

[0056] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 93.65 gof piperidine were dissolved in 75 ml of methanol. 75.76 g of methylacrylate were added dropwise to the solution while stirring. The productwas left to stand for 24 hours. The methanol and the excess methylacrylate were then distilled off under reduced pressure via a rotaryevaporator.

EXAMPLE 5

[0057] Synthesis of a catalyst from Dimethyl Maleate andN,N-bis(3-dimethylaminopropyl)amine

[0058] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 84.77 gof N,N-bis(3-dimethylaminopropyl)amine were dissolved in 75 ml ofmethanol. 65.23 g of dimethyl maleate were added dropwise to thesolution while stirring. The product was then heated to 60 for 2 hours.Stirring was then carried out for 24 hours at room temperature. Themethanol was then distilled off under reduced pressure via a rotaryevaporator.

Example 6

[0059] 40 Synthesis of a Catalyst from Morpholine and Methyl Acrylate

[0060] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration), and internal thermometer, 95.83 gof morpholine were dissolved in 150 ml of methanol. 86.09 g of methylacrylate were added dropwise to the solution while stirring. Stirringwas carried out at room temperature. The methanol and the excessmorpholine were then distilled off under reduced pressure via a Vigreuxcolumn.

Example 7

[0061] Synthesis of a Catalyst from Aminopropylimidazole and MethylAcrylate

[0062] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 62.58 gof aminopropylimidazole were dissolved in 75 ml of methanol. 107.6 g ofmethyl acrylate were added dropwise to the solution while stirring. Themixture was left to stand for 48 hours. The methanol and the excessmethyl acrylate were then distilled off under reduced pressure via aVigreux column.

Example 8

[0063] Synthesis of a Catalyst from Methyl Acrylate andN-(2-aminoethyl)morpholine

[0064] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, .65.1 gof N-(2-aminoethyl)morpholine were dissolved in 75 ml of methanol. 107.6g of methyl acrylate were added dropwise to the solution while stirring.The mixture was left to stand for 48 hours. The methanol and the excessmethyl acrylate were then distilled off under reduced pressure via aVigreux column.

Example 9

[0065] Synthesis of a Catalyst from Methyl Acrylate andN,N-bis(3-dimethylaminopropyl)amine

[0066] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 93.65 gof N,N-bis(3-dimethylaminopropyl)amine were dissolved in 75 ml ofmethanol. 47.33 g of methyl acrylate were added dropwise to the solutionwhile stirring.

[0067] Stirring was carried out for 24 hours at room temperature. Themethanol and the excess methyl acrylate were then distilled off underreduced pressure via a rotary evaporator.

Example 10

[0068] Preparation of a Comparative Flexible Foam

[0069] 750 g of polyol component were mixed with 361 g of isocyanatecomponent (index 90) and the foaming material was transferred to analuminum mold (40 cm×40 cm×10 cm) thermostated at 50° C., the componentshaving the following compositions:

[0070] Polyol Component:

[0071] 97 parts by weight of Lupranol®2090, molecular weight: δ 000, OHnumber: 28 (Elastogran GmbH)

[0072] 3 parts by weight of Lupranol® 2047, molecular weight 4 000, OHnumber: 42 (Elastogran GmbH)

[0073] 3.31 parts by weight of water

[0074] 0.6 part by weight of 2-(2-dimethylaminoethoxy)ethanol

[0075] 0.5 part by weight of Tegostab® B8631 (Goldschmidt)

[0076] 0.8 part by weight of aminopropylimidazole (BASF Aktiengesell-schaft)

[0077] Isocyanate Component:

[0078] A mixture of 42 parts of Lupranat® M 20 W (polymer MDI,Elastogran GmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts ofLupranat® ME and 47 parts of Lupranat® MI, Elastogran GmbH)

[0079] After 5 minutes the prepared flexible foam was removed from themold. The characterization of this foam and the reaction parameters(recorded for a cup foam having the same formulation and same index) areshown in table 1.

Example 11

[0080] Preparation of a Flexible Foam Using the Catalyst from Example 3

[0081] 750 g of polyol component were mixed with 360 g of isocyanatecomponent (index 90) and the foaming material was transferred to analuminum mold (40 cm×40 cm×10 cm) thermostated at 50° C., the componentshaving the following compositions:

[0082] Polyol Component

[0083] 97 parts by weight of Lupranol® 2090, molecular weight: δ 000, OHnumber: 28 (Elastogran GmbH)

[0084] 3 parts by weight of Lupranol® 2047, molecular weight 4 000, OHnumber: 42 (Elastogran GmbH)

[0085] 3.31 parts by weight of water

[0086] 0.6 part by weight of 2-(2-dimethylaminoethoxy)ethanol

[0087] 0.5 part by weight of Tegostab® B8631 (Goldschmidt)

[0088] 0.8 part by weight of catalyst from example 3

[0089] Isocyanate Component

[0090] mixture of 42 parts of Lupranat® M 20 W (polymer MDI, ElastogranGmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts of Lupranat® ME and47 parts of Lupranat® MI, Elastogran GmbH)

[0091] After 5 minutes, the prepared flexible foam was removed from themold. The properties of this foam and the reaction parameters (recordedfor a cup foam having the same formulation and same index) are comparedwith those of the foam from example 10 in table 1.

[0092] In order to simulate conditions as in abovementioned specialapplications in which polyurethane materials are exposed to hydrolyticstresses and to obtain foams having measurable contents of aromaticamines, the storage under moist and warm conditions was carried out. Forthis purpose, in each case sample cubes having an edge length of 3 cmwere stored at 90° C. and 90% relative humidity for 72 hours in aconditioned chamber. The extraction of the aromatic amines was carriedout by means of a method developed by Prof. Skarping, University ofLund. For this purpose, the foam was pressed out 10 times in 10 ml ofacetic acid (w=1% by weight). The acetic acid was transferred to a 50 mlvolumetric flask while the foam sample was compressed. The procedure wasrepeated twice and the volumetric flask then made up to the mark withacetic acid (w=1% by weight). The MDA content of the combined extractswas then determined by means of capillary electrophoresis with UVdetection (apparatus type: Biofocus 3 000, measurement of the peak areasand comparison with imidazole as internal standard). The MDA contentsshown in table 1 correspond to the absolute contents of the resultingMDA in the PUR foam. TABLE 1 Foam characterization and reactionparameters Foam from Foam from example 10 example 11 Cream time 14 s 14s Gel time 85 s 110 s Rise time 127 s 155 s Free-foamed density 45.4 g/l44.3 g/l CS 3.7% 4.9% CS after storage under 11.6% 7.3% moist and warmconditions Δ CS 7.9% 2.4% RES 68% 63% RES after storage under 50% 57%moist and warm conditions Δ RES 18% 6% CR 6.0 kPa 5.8 kPa CR afterstorage under 4.2 kPA 5.0 kPa moist and warm conditions Δ CR 1.8 kPa 0.8kPa 4,4′-MDA <1 ppm <1 ppm 2,4′-MDA <1 ppm <1 ppm 4,4′-MDA after storageunder 554 ppm 100 ppm moist and warm conditions 2,4′-MDA after storageunder 828 ppm 208 ppm moist and warm conditions

[0093] As shown by the data in table 1, the novel catalyst leads to afoaming reaction which is only insignificantly slower than that usingthe conventional incorporatable catalyst aminopropylimidazole. Themechanical properties (CS, RES, CR), too, are only slightly differentwith the novel catalyst in the unaged state compared with thecomparative foam. However, after storage under moist and warmconditions, these values are substantially poorer in the case of thecomparative foam than in the case of the foam which is preparedaccording to the invention and for which the mechanical values change toa far lesser extent. After storage under moist and warm conditions,moreover, substantially less MDA is found in the novel foam than in thecomparative foam.

EXAMPLE 12

[0094] Synthesis of a Catalyst from 1-(2-hydroxyethyl)piperazine andDimethyl Itaconate

[0095] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 60 g of1-(2-hydroxyethyl)piperazine were dissolved in 60 ml of ethanol. 72.88 gof dimethyl itaconate were added dropwise to the solution whilestirring. Heating was carried out to 70° C. and stirring was effectedfor 6 hours under reflux at this temperature. The methanol was thendistilled off under reduced pressure by a rotary evaporator.

Example 13

[0096] Preparation of a Flexible foam Using the Catalyst from Example 12

[0097] 750 g of polyol components were mixed with 365 g of isocyanatecomponent (index 90) and the foaming material was transferred to analuminum mold (40 cm×40 cm×10 cm), thermostated at 50° C., thecomponents having the following compositions:

[0098] Polyol Component:

[0099] 97 parts by weight of Lupranol® 2090, molecular weight: 6000, OHnumber: 28 (Elastogran GmbH)

[0100] 3 parts by weight of Lupranol® 2047, molecular weight: 4000, OHnumber: 42 (Elastogran GmbH)

[0101] 3.31 parts by weight of water

[0102] 0.6 part by weight of 2-(2-dimethylaminoethoxy)ethanol

[0103] 0.5 part by weight of Tegostab® B8631 (Goldschmidt)

[0104] 0.8 part by weight of catalyst from example 12

[0105] Isocyanate Component:

[0106] Mixture of 42 parts of Lupranat® M 20 W (polymer MDI, ElastogranGmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts of Lupranat® ME and47 parts of Lupranat® MI, Elastogran GmbH)

[0107] After 5 minutes, the prepared flexible foam was removed from themold. The properties of this foam and the reaction parameters (recordedfor a cup foam having the same formulation and same index) are comparedwith those of the foam from example 10 in table 2.

[0108] In order to simulate conditions as in abovementioned specialapplications in which polyurethane materials are exposed to hydrolyticstresses and to obtain foams having measurable contents of aromaticamines, storage under moist and warm conditions and extraction of foamsamples as described under example 11 were carried out. The MDA contentof the combined extracts was then determined by means of capillaryelectrophoresis with UV detection (apparatus type: Biofocus 3000,measurement of the peak areas and comparison with imidazole as internalstandard). The MDA contents shown in table 2 correspond to the absolutecontents of the resulting MDA in the PUR foam. TABLE 2 Foamcharacterization and reaction parameters Foam from Foam from example 10example 13 Cream time 14 s 16 s Gel time 85 s 95 s Rise time 127 s 167 sFree-foamed density 45.4 g/l 42.5 g/l CS 3.7% 4.6% CS after storageunder 11.6% 7.6% moist and warm conditions Δ CS 7.9% 3.0% RES 68% 65%RES after storage under 50% 61% moist and warm conditions Δ RES 18% 4%CR 6.0 kPa 7.7 kPa CR after storage under 4.2 kPA 6.8 kPa moist and warmconditions Δ CR 1.8 kPa 0.9 kPa Fogging 0.22 mg 0.29 mg 4,4′-MDA <1 ppm<1 ppm 2,4′-MDA <1 ppm <1 ppm 4,4′-MDA after storage under 554 ppm 62ppm moist and warm conditions 2,4′-MDA after storage under 828 ppm 147ppm moist and warm conditions

[0109] As shown by the data in table 2, the novel catalyst leads to afoaming reaction which is only insignificantly slower than that usingthe conventional incorporatable catalyst aminopropylimidazole. Themechanical properties (CS, RES, CR), too, are only slightly differentwith the novel catalyst in the unaged state compared with thecomparative foam. However, after storage under moist and warm conditionsthese values are substantially poorer in the case of the comparativefoam than in the case of the foam which is prepared according to theinvention and for which the mechanical values change to a far lesserextent. After storage under moist and warm conditions, moreover,substantially less MDA is found in the novel foam than in thecomparative foam.

Example 14

[0110] Synthesis of a Catalyst from 1-(2-hydroxyethyl)piperazine andDibutyl Maleate

[0111] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 40 g of1-(2-hydroxyethyl)piperazine were dissolved in 40 ml of methanol. 70.14g of dibutyl maleate were added dropwise to the solution while stirring,the temperature being kept at about 35° C. The reaction mixture was leftto stand for 24 hours. The methanol was then distilled off under reducedpressure by a rotary evaporator.

Example 15

[0112] Preparation of a Flexible Foam Using the Catalyst from Example 14

[0113] 750 g of polyol component were mixed with 365 g of isocyanatecomponent (index 90) and the foaming material was transferred to analuminum mold (40 cm×40 cm×10 cm) thermostated at 50° C., the componentshaving the following compositions:

[0114] Polyol Component:

[0115] 97 parts by weight of Lupranol® 2090, molecular weight: 6000, OHnumber: 28 (Elastogran GmbH)

[0116] 3 parts by weight of Lupranol® 2047, molecular weight 4000, OHnumber: 42 (Elastogran GmbH)

[0117] 3.31 parts by weight of water

[0118] 0.6 part by weight of 2-(2-dimethylaminoethoxy)ethanol

[0119] 0.5 part by weight Tegostab® B8631 (Goldschmidt)

[0120] 0.8 part by weight of catalyst from example 14

[0121] Isocyanate Component:

[0122] Mixture of 42 parts of Lupranat® M 20 W (polymer MDI, ElastogranGmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts of Lupranat® ME and47 parts of Lupranat® MI, Elastogran GmbH)

[0123] After 5 minutes, the prepared flexible foam was removed from themold. The properties of this foam and the reaction parameters (recordedfor a cup foam having the same formulation and same index) are comparedwith those of the foam from example 10 in table 3.

[0124] In order to simulate conditions as in abovementioned specialapplications in which polyurethane materials are exposed to hydrolyticstresses and to obtain foams having measurable contents of aromaticamines, storage under moist and warm conditions and extraction of foamsamples as described under example 11 were carried out. The MDA contentof the combined extracts was then determined by means of capillaryelectrophoresis with UV detection (apparatus type: Biofocus 3000,measurement of the peak areas and comparison with imidazole as internalstandard). The MDA contents shown in table 3 correspond to the absolutecontents of the resulting MDA in the PUR foam. TABLE 3 Foamcharacterization and reaction parameters Foam from Foam from example 10example 15 Cream time 14 s 21 s Gel time 85 s 100 s Rise time 127 s 165s Free-foamed density 45.4 g/l 43.1 g/l CS 3.7% 4.6% CS after storageunder 11.6% 8.4% moist and warm conditions Δ CS 7.9% 3.8% RES 68% 62%RES after storage under 50% 56% moist and warm conditions Δ RES 18% 6%CR 6.0 kPa 6.3 kPa CR after storage under 4.2 kPA 4.9 kPa moist and warmconditions Δ CR 1.8 kPa 1.4 kPa Fogging 0.22 mg 0.25 mg 4,4′-MDA <1 ppm<1 ppm 2,4′-MDA <1 ppm <1 ppm 4,4′-MDA after storage under 554 ppm 214ppm moist and warm conditions 2,4′-MDA after storage under 828 ppm 401ppm moist and warm conditions

[0125] As shown by the data in table 3, the novel catalyst leads to afoaming reaction which is only insignificantly slower than that usingthe conventional incorporatable catalyst aminopropylimidazole. Themechanical properties (CS, RES, CR), too, are only slightly differentwith the novel catalyst in the unaged state compared with thecomparative foam. However, after storage under moist and warm conditionsthese values are substantially poorer in the case of the comparativefoam than in the case of the foam which is prepared according to theinvention and for which the mechanical values change to a far lesserextent. After storage under moist and warm conditions, moreover,substantially less MDA is found in the novel foam than in thecomparative foam.

Example 16

[0126] Synthesis of a Catalyst from 1-(2-hydroxyethyl)piperazine andDiethyl Maleate

[0127] In a 500 ml four-necked flask with a reflux condenser, droppingfunnel (with pressure equilibration) and internal thermometer, 30 g of1-(2-hydroxyethyl)piperazine were dissolved in 30 ml of methanol. 39.68g of diethyl maleate were added dropwise to the solution while stirring,the temperature being kept at about 35° C. The reaction mixture was leftto stand for 24 hours. The methanol was then distilled off under reducedpressure by a rotary evaporator, the product crystallizing out.

Example 17

[0128] Preparation of a Flexible Foam Using the Catalyst from Example 16

[0129] 750 g of polyol component and 365 g of isocyanate component(index 90) were mixed and the foaming material was transferred to analuminum mold (40 cm×40 cm×10 cm) thermostated at 50° C., the componentshaving the following compositions:

[0130] Polyol Component:

[0131] 97 parts by weight of Lupranol® 2090, molecular weight: 6000, OHnumber: 28 (Elastogran GmbH)

[0132] 3 parts by weight of Lupranol® 2047, molecular weight 4000, OHnumber: 42 (Elastogran GmbH)

[0133] 3.31 parts by weight of water

[0134] 0.6 part by weight of 2-(2-dimethylaminoethoxy)ethanol

[0135] 0.5 part by weight of Tegostab® B8631 (Goldschmidt)

[0136] 0.8 part by weight of catalyst from example 16

[0137] Isocyanate Component:

[0138] Mixture of 42 parts of Lupranat® M 20 W (polymer MDI, ElastogranGmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts of Lupranat® ME and47 parts of Lupranat® MI, Elastogran GmbH)

[0139] After 5 minutes the prepared flexible foam was removed from themold. The properties of this foam and the reaction parameters (recordedfor a cup foam having the same formulation and same index) are comparedwith those of the foam from example 10 in table 4.

[0140] In order to simulate conditions as in abovementioned specialapplications in which polyurethane materials are exposed to hydrolyticstresses and to obtain foams having measurable contents of aromaticamines, storage under moist and warm conditions and extraction of foamsamples as described under example 11 were carried out. The MDA contentof the combined extracts was then determined by means of capillaryelectrophoresis with UV detection (apparatus type: Biofocus 3000,measurement of the peak areas and comparison with imidazole as internalstandard). The MDA contents shown in table 4 correspond to the absolutecontents of the resulting MDA in the PUR foam. TABLE 4 Foamcharacterization and reaction parameters Foam from Foam from example 10example 17 Cream time 14 s 21 s Gel time 85 s 101 s Rise time 127 s 163s Free-foamed density 45.4 g/l 44.3 g/l CS 3.7% 4.4% CS after storageunder 11.6% 8.4% moist and warm conditions Δ CS 7.9% 4% RES 68% 66% RESafter storage under 50% 57% moist and warm conditions Δ RES 18% 9% CR6.0 kPa 6.3 kPa CR after storage under 4.2 kPa 5.0 kPa moist and warmconditions Δ CR 1.8 kPa 1.3 kPa Fogging 0.22 mg 0.20 mg 4,4′-MDA <1 ppm<1 ppm 2,4′-MDA <1 ppm <1 ppm 4,4′-MDA after storage under 554 ppm 151ppm moist and warm conditions 2,4′-MDA after storage under 828 ppm 299ppm moist and warm conditions

[0141] As shown by the data in table 4, the novel catalyst leads to afoaming reaction which is only insignificantly slower than that usingthe conventional incorporatable catalyst aminopropylimidazole. Themechanical properties (CS, RES, CR), too, are only slightly differentwith the novel catalyst in the unaged state compared with thecomparative foam. However, after storage under moist and warmconditions, these values are substantially poorer in the case of thecomparative foam than in the case of the foam which is preparedaccording to the invention and for which the mechanical values change toa far lesser extent. After storage under moist and warm conditions,moreover, substantially less MDA is found in the novel foam than in thecomparative foam.

Example 18

[0142] Preparation of a Flexible Foam Using the Catalyst from Example 12in Addition to Aminopropylimidazole

[0143] 750 g of polyol component were mixed with 363 g of isocyanatecomponent (index 90) and the foaming material was transferred to analuminum mold (40 cm×40 cm×10 cm) thermostated at 50° C., the componentshaving the following composition:

[0144] Polyol Component:

[0145] 97 parts by weight of Lupranol® 2090, molecular weight: 6000, OHnumber: 28 (Elastogran GmbH)

[0146] 3 parts by weight of Lupranol® 2047, molecular weight 4000, OHnumber: 42 (Elastogran GmbH)

[0147] 3.31 parts by weight of water

[0148] 0.6 part by weight of 2-(2-dimethylaminoethoxy)ethanol

[0149] 0.5 part by weight of Tegostab® B8631 (Goldschmidt)

[0150] 0.8 part by weight of aminopropylimidazole (BASFAktiengesellschaft)

[0151] 0.8 part by weight of catalyst from example 12

[0152] Isocyanate Component:

[0153] Mixture of 42 parts of Lupranat® M 20 W (polymer MDI, ElastogranGmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts of Lupranat® ME and47 parts of Lupranat® MI, Elastogran GmbH)

[0154] After 5 minutes, the prepared flexible foam was removed from themold. The properties of this foam and the reaction parameters (recordedfor a cup foam having the same formulation and same index) are comparedwith those of the foam from example 10 in table 5.

[0155] In order to simulate conditions as in abovementioned specialapplications in which polyurethane materials are exposed to hydrolyticstresses and to obtain foams having measurable contents of aromaticamines, storage under moist and warm conditions and extraction of foamsamples as described under example 11 were carried out. The MDA contentof the combined extracts was then determined by means of capillaryelectrophoresis with UV detection (apparatus type: Biofocus 3000,measurement of the peak areas and comparison with imidazole as internalstandard). The MDA contents shown in table 5 correspond to the absolutecontents of the resulting MDA in the PUR foam. TABLE 5 Foamcharacterization and reaction parameters Foam from Foam from example 10example 10 Cream time 14 s 13 s Gel time 85 s 74 s Rise time 127 s 122 sFree-foamed density 45.4 g/l 43.0 g/l CS 3.7% 3.8% CS after storageunder 11.6% 6.7% moist and warm conditions Δ CS 7.9% 2.9% RES 68% 67%RES after storage under 50% 59% moist and warm conditions Δ RES 18% 8%CR 6.0 kPa 5.8 kPa CR after storage under 4.2 kPA 5.0 kPa moist and warmconditions Δ CR 1.8 kPa 0.8 kPa Fogging 0.22 mg 0.19 mg 4,4′-MDA <1 ppm<1 ppm 2,4′-MDA <1 ppm <1 ppm 4,4′-MDA after storage under 554 ppm 122ppm moist and warm conditions 2,4′-MDA after storage under 828 ppm 264ppm moist and warm conditions

[0156] As shown by the data in table 5, the reaction rate of thepolyurethane system can be increased in comparison with the sole use ofthe novel catalyst (cf. example 13) by combining the novel catalyst withanother catalyst. The mechanical properties (CS, RES, CR), are onlyslightly different with the novel catalyst in the unaged state comparedwith the comparative foam without novel catalyst. However, after storageunder moist and warm conditions, these values are substantially poorerin the case of the comparative foam than in the case of the foam whichis prepared according to the invention and for which the mechanicalvalues change to a far lesser extent. After storage under moist and warmconditions, moreover, substantially less MDA is found in the novel foamthan in the comparative foam. This example shows that the novelcatalysts, together with other catalysts, can advantageously be used asadditives for improving the mechanical properties and reducing theformation of aromatic amines after storage under moist and warmconditions.

Example 19

[0157] Catalytic Activity of the Catalyst from Example 16

[0158] In order to be able to assess the catalytic activity of thecatalyst from example 16, foaming experiments were carried out in whicheither no catalyst or only this catalyst was used.

Comparative Experiment Without Addition of Catalyst:

[0159] 100 g of polyol component were mixed with 48.5 g of isocyanatecomponent (index 90) in a polyethylene bucket having a capacity of 1.1l, the components having the following compositions:

[0160] Polyol Components:

[0161] 97 parts by weight of Lupranol® 2090, molecular weight: 6000, OHnumber: 28 (Elastogran GmbH)

[0162] 3 parts by weight of Lupranol® 2047, molecular weight 4000, OHnumber: 42 (Elastogran GmbH)

[0163] 3.31 parts by weight of water

[0164] 0.5 part by weight of Tegostab® B8631 (Goldschmidt)

[0165] Isocyanate Components:

[0166] Mixture of 42 parts of Lupranat® M 20 W (polymer MDI, ElastogranGmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts of Lupranat® ME and47 parts of Lupranat® MI, Elastogran GmbH)

[0167] The reacting material began to foam after 60 seconds (cream time)but then collapsed completely, so that no useable flexible polyurethanefoam was obtained. The gel time of the collapsed material was 660seconds.

[0168] Experiment Using the Novel Catalyst from Example 16:

[0169] 100 g of polyol component were mixed with 48.1 g of isocyanatecomponent (index 90) in a polyethylene bucket having a capacity of 1.11, the components having the following compositions:

[0170] Polyol Components:

[0171] 97 parts by weight of Lupranol® 2090, molecular weight: 6000, OHnumber: 28 (Elastogran GmbH)

[0172] 3 parts by weight of Lupranol® 2047, molecular weight 4000, OHnumber: 42 (Elastogran GmbH)

[0173] 3.31 parts by weight of water

[0174] 0.5 part by weight of Tegostab® B8631 (Goldschmidt)

[0175] 4 parts by weight of catalyst from example 16

[0176] Isocyanate Component:

[0177] Mixture of 42 parts of Lupranat® M 20 W (polymer MDI, ElastogranGmbH) and a mixture of 2,4′- and 4,4′-MDI (11 parts of Lupranat® ME and47 parts of Lupranat® MI, Elastogran GmbH)

[0178] The reacting material began to foam after 29 seconds (cream time)and formed a stable flexible polyurethane foam. The gel time of the foamwas 220 seconds.

[0179] These experiments show that the novel catalyst from example 16has sufficient catalytic activity for obtaining a stable foam, which wasnot possible without the catalyst.

We claim:
 1. A catalyst containing, as structural units, at least onetertiary amino group and at least one group which, after itsdecomposition, is capable of complexing or protonating the tertiaryamino group, and the catalyst containing at least just as many or moregroups which are decomposable and, after decomposition, have acomplexing or protonating action as they have catalytically activecenters.
 2. A catalyst as claimed in claim 1, wherein the decompositionis effected by hydrolysis.
 3. A catalyst as claimed in claim 1, whichcatalyzes the reaction of isocyanates with compounds reactive towardisocyanates.
 4. A catalyst containing at least one tertiary amino groupas a structural unit and at least one structural unit selected from thefollowing group: carboxylic esters, sulfonic esters, carboxylicanhydrides, lactones, sultones, phosphoric esters and/or phosphonicesters, the catalyst containing at least just as many or more groupswhich are decomposable and, after decomposition, have a complexing orprotonating action as they have catalytically active centers.
 5. Acatalyst as claimed in any of claims 1 to 4, which has at least onegroup reactive toward isocyanates.
 6. A process for the preparation ofpolyisocyanate polyadducts, wherein a catalyst as claimed in any ofclaims 1 to 5 is used.
 7. A process for the preparation of flexiblepolyurethane foams, wherein a catalyst as claimed in any of claims 1 to5 is used.
 8. A polyisocyanate polyadduct containing a catalyst asclaimed in any of claims 1 to
 5. 9. A flexible polyurethane foamcontaining a catalyst as claimed in any of claims 1 to
 5. 10. The use ofa catalyst as claimed in any of claims 1 to 5 for the preparation ofpolyisocyanate polyadducts.